<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <script>
    var str = 'qwerwaeqweqwe'

    // console.log( str[5] )
    // console.log( str.charAt(5) )
    // console.log( str.charCodeAt(5) )
    
    var count = 0
    for(var i = 0; i < str.length; i++) {
      if(str[i] === 'q') {
        count += 1
      }
    }
    console.log(count)
  </script>
</body>
</html>